Residuum soils are most likely formed from which type of rock?

Residuum soils are formed from the in situ weathering of rock material, meaning they develop directly from the underlying bedrock without significant transportation of materials. Metamorphic rocks, characterized by their alteration under heat and pressure, often break down into mineral components that contribute to the formation of residuum soils. These soils typically inherit properties from the metamorphic rock, which can include a variety of mineral types and compositions influenced by the original rock's characteristics.

While other types of rocks can contribute to soil formation—igneous rocks might yield sandy or clayey soils, and sandstone can produce relatively sandy soils—the nature of metamorphic rocks offers a more complex source of mineral diversity that aids in developing rich, layered soils. Thus, residuum soils are most commonly associated with metamorphic rocks due to their formation process and resultant soil characteristics.